Abstract:

In the cut pipe inspection and simulated cleaning test after engineering cleaning，it was found that the local oxide skin peeling part appeared a corrosion pit of more than 400 microns. The reasons for the formation of corrosion pit are analyzed. Analysis results show that the regional and local scale dissolved metal oxide skin peeling bare area, will form the “large cathode” and“small anode” battery corrosion effect, accelerated the corrosion of metals, the partial oxidation of skin peeling parts generated serious corrosion pit. Therefore, it is necessary to evaluate the corrosion control effect with the actual pipe sample when the chemical cleaning of the oxide skin of superheater is carried out simultaneously.

Key words:

superheater, oxide skin, spalling, chemical cleaning, local corrosion, battery effect